Shoe soles with twistable shank



Aug. 4, 1959 J. SCHALLER SHOE SOLES WITH' TWISIABLE SHANK Filed Dec. 13, 1955 2,897,611 snort. sores TWISTABLE Johannes Schaller, Offenbach (Main), Germany Application December 13, B55, Serial. No. 552,945 Claims priority, application Germany December 20, 1954 1 Claim. (CI. 36-30) The present mv'ention relates to new improvements in shoes, and more particularly to soles of leather, rubber, synthetic material, or the like, wherein the front and. heel portions ar turnable or pivotable releative to each other.

Prior to this invention, various efforts have been made to produce soles which adapt themselves to the natural movements of the foot and resist such movements as little as possible. For this purpose, the sole was shaped, for example, to conform with the tracks left on the ground by a human foot, which means that the inner edge of the shank portion was drawn inwardly to such an extent that the outer edge portion of the sole would only form a narrow bridge between the front and heel portions. To obtain the proper flexibility of the shank portion, another design proposed that this portion be strongly drawn in from both sides. Both designs thus deviate considerably from the usual shank design of a sole in which the inner side extends along a flat curve and the outer side almost along a straight line.

The production of shoes with soles of such concavecurved shanks has met with considerable technical difficulties. Also, the average purchaser cares very little for such unusual shapes, apart from the fact that by thus cutting out the soles, the foot is left very little, protected.

It is one of the objects of the present invention toprovide a sole with a twistable shank portion which eliminates the above-mentioned disadvantages by providing such shank portion of the outer or inner sole or of both soles with one or more cutout portions and by filling out or bridging such cutout portions with a material which is softer than that of the respective sole.

Another object of the invention is thus to provide a sole with a twistable shank portion of a width which conforms to that of the customary relatively inflexible shank portion, that is, one which substantially corresponds to the size and shape in accordance with a vertical projection of the foot.

An important feature of such a sole designed according to the invention is that the foot will thus be equally well protected and supported as by the customary, relatively inflexible soles which are drawn inwardly only very little at the shank portion.

The size and shape of the cutout portion or portions and the corresponding filled-in portion of a softer, more easily pliable material depends upon the particular design of the shoe and the degree of flexibility and twistabi-lity desired. Thus, for example, the cutouts may be made of greater width near the edge or edges of the sole than tow-and the middle of the shank portion. The degree of flexibility and twistability may also be varied by providing only one cutout portion of a width smaller than that of the entire shank portion, and preferably by pro viding such cutout portion on the outer side of the sole, or by providing .two such cutout and refilled portions on opposite sides and by preferably making them or different dimensions or by providing one continuous cutout and refilled portion which extends from one edge of lice 2 the shank portion of the sole to the other and is of nar= rower width at its central part. Further variations ac cording to the inventions in order to obtain different degrees of flexibility and twis-tability may consist in providing one type ofcutout portion in one sole, for example, the inner sole, and another type of cutout in the other sole, or two cutouts in one sole and none or only one in the other sole. The front and heel portions of the sole may also be made of two separate pieces of material which are connected with each other by a softer and more flexible material. In such a manner it will also be possible to utilize scrap leathen and to make the heel portion of the sole of an inferior grade of leather or other material than the front portion. The cutouts at the opposite sides of one sole or at the same or different sides of both soles may also be provided at different points so as not to coincide with each other. Regardless of whether a cutout and refilled portion is provided on only one side or on both 'sides of the sole, or. whether such cutout extends from one side to the other, I have found that a wedge-shaped cutout which is preferably rounded off or curved at the central part of the sole is the most suitable.

The material to be used according to the invention for filling out the cutout portions or to connect the front and rear port-ions of the sole may be any kind of elastomeric material, such as sponge rubber, crude or vulcanized rubber, or an elastic synthetic material such as polyethylene or thelike.

Further objects, features, and advantages of the present invention willappear from the following detailed description thereof and the accompanying diagrammatic drawings, in which- Fig. 1 shows a plan view of a shoe sole according to the invention consisting of an outer and inner sole, each of which is provided with two cutouts within the area of the shank. portion which are filled in by means of inserts of elastic material;

.Fig. 2 shows a plan view of a shoe sole which likewise comprises an outer and inner sole each of which consists of two pieces of sole material, such as leather or other tough material, which are connected to each other by means of a single insert of elastic material; while Fig. 3 shows a portion of a shoe sole which likewise comprises an outer and inner sole in each of which only one substantially wedge-shaped cutout is provided which is filled out with an elastic material.

Referring to the drawings, and first particularly to Fig. 1, the shoe sole consists of an outer sole 1 upon which an insole Z is superimposed. Although the present invention and twistability of the soles obviously also affects the shoe upper, the same, as well as the manner of securing it between the outer and inner soles 1 and 2 has not been illustrated in the drawings. Within the area of the shank portion, both the outer and inner soles 1 and 2 as shown in Fig. 1 are each provided with two cutouts which are limited by the edges 3 and 4 which have portions located within substantially the same vertical plane. The cutouts are filled out completely with inserts 5 and 6, respectively, which consist of a material which is softer and more elastic than that of the sole proper. The inserts 5 and 6 may be secured to the adjacent edges of the sole in any suitable manner which largely depends upon the type of materials used. Thus, for example, they may be cemented to the sole proper or they may be molded thereto in -a liquid or pliant condition so as to combine therewith. Inserts 6 in the inner sole may consist of the same or a different material as inserts 5 in the outer sole.

The modification of the invention as shown in Fig. 2 shows outer and inner. soles, each of which consists of separate front and heel portions 7, 9 and 8, 10, re-

spectively. This permits the use of much smaller pieces of sole material and thus avoids much of the waste usually accompanying the making of full soles. Also, since the heel portion of the outer sole is subjected to less Wear than the front portion thereof, an inferior grade of material may be used for such heel portion without thereby rendering the entire shoe in any way inferior in quality. The two portions of each'so'le are then connected by means of inserts 11 land 12, respectively, of elastic material in a similar manner as described with respect to Fig. 1 so as to form two complete soles. The two portions of each sole are preferably made of a shape as shown in Fig. 2 wherein the portions 7, 9 and 8, 10 are longer in the center than along the outer edges thereof and the inserts are of substantially double-wedge shape widening toward the opposite outer edges.

Fig. 3 illustrates two other modifications of the invention. The outer sole 13 and the insole 14 may be provided with corresponding wedge-shaped cutouts so that the edges thereof are directly superimposed to each other. The inserts 15 and 16 are again of a softer, more pliable material and are permanently secured to the edges of the respective cutouts.

Obviously, instead of the wedgelike shape of the cutouts and inserts as shown in the drawings, these portions may be made of any other suitable shape to provide the desired flexibility and twistabi'lity of the sole or soles or to correspond with other design features of the shoe. Also, if the outer sole is made of a thin, soft material, only the inner sole may 'be provided with the cutouts and soft inserts.

These inserts according to the invention will thus completely fill out the corresponding cutouts in the sole and connect the respective portions of the sole turnably and twistably to each other. Thus, the difierent portions of the sole or soles of the shoe will be able to turn or pivot and twist relative to each other both around its longitudinal and transverse axes without diminishing the protective width of the shank portion. Such soles may be secured to the uppers in the same manner as any ordinary soles which are made of a single piece of material. Any possible spaces left between the outer and inner soles including the elastic inserts may also be filled out by suitable filling materials such as are customary in the art.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, 'but is capable of numerous modifications within the scope of the appended claim.

Having thus fully disclosed my invention, what I claim is:

A shoe sole comprising, a sole portion; a heel portion spaced longitudinally from said sole portion; and a shank portion intermediate and connecting said sole and heel portions, said sole, shank and heel portions having lateral edges in continued mutual alignment; said shank portion including inserted therein and connected therewith a first wedge-shaped insert portion extending along and tapering from one of said lateral edges towards said center of said shank portion, a second Wedge-shaped insert portion extending along and tapering from the other of said lateral edges towards said center, and a third insert portion intermediate and integrally connecting said first and second insert portions and having a dimension longitudinally of said sole substantially less than the maximum dimension of said first and second insert portions in the same direction, said insert portions extending through the entire thickness of said sole forming part of the same and being more flexible than the other portions thereof, for substantially reducing the resistance of said sole in said shank portion against twisting about a line extending longitudinally of said sole, whereby the sole structure will be capable to follow the natural movement of the foot during walking.

References Cited in the file of this patent UNITED STATES PATENTS 350,705 Strickland Oct. 12, 1886 694,872 Lockett Mar. 4, 1902 1,964,364 Pellkofer June 26, 1934 2,227,352 Krasnosky Dec. 31, 1940 2,314,237 Muller Mar. 16, 1943 FOREIGN PATENTS 52,724 France June 12, 1944 69,656 Norway Oct. 15, 1943 74,739 Switzerland Sept. 1, 1917 237,774 Switzerland Sept. 17, 1945 1 238,679 Switzerland Nov, 16, 1945 888,860 France Sept. 20, 1943 

